Axle/differential for 1000 hp?

[ghinmi]

First post! I'm looking for some help on axle selection for my latest project. The part that throws everything for a loop is that it will make a little over 1000 hp at 3200 lbs and I will be drag racing it with slicks on occasion. The determining factor (in my mind) is differential selection. If it was a pure drag car I'd do a spool or locker with 35 spline axles but that would be less than ideal around corners. I'm having a hard time finding a good differential that can take the abuse and still be good around corners. I see that they make a 33 spline true-trac for the 12 bolt and a 35 spline s-trac for the 9", what is everyone's opinion on those? Any other suggestions?

[NOPANTS68]

From what I understand the new Wavetrac is supposed to hold that kind of power and be streetable. A buddy just got his for his 9 inch going into a full weight '68 Chevelle making 1250 RW. The Wavetrac folks insisted that it would take it all day long.

[slow4dr]

The 35 spline set-ups with Platinum/Wave tracs are exactly what you need. You'll also want to upgrade the housing, pinion support and yoke as well.


-J

[will69camaro]

Details on upgraded housing? I'm planning on 900-1000 with mine. I have the DSE rearend (9"). I'm ok with the previously mentioned upgrades. I'll see how long the 31 spline's last but I know they'll be changed eventually.

[slow4dr]

Currie calls it their "Sportsman" case and it's Nodular iron with extra material in the right places. The pinion support and yoke they sell as an upgrade are billet.

[69znc]

At 1000 hp and street driven there are many options. Dana, 9 inch... any major manufacturer can provide the needed components. First the question is what is rear wheel not engine dyno and then how much rubber can you run. 335 with tubed wells, axle is not the issue. Figure out how far you are going for tire fitment, how big of wells and what is the weight and work back from that. The HP is a singular dimension.

[FETorino]

They build diffs for race cars.

http://www.dpiracingproducts.com/products/super-max-platinum-differential-1-2-tight.html

[intocarss]

I ran a 9" with 35 spline axles, a spool (total drag car) and the rear housing was braced. The car weighed 3018 w/driver and made 1000+ Hp, 1.20 60". Ran 14/32 slicks and never in 12 years did I see any signs of twisting an axle. BTW make sure the axles you get are streetable

Here's an intreresting chart on axles

http://qp.doonce.com/axle_tech.htm

[ghinmi]

At 1000 hp and street driven there are many options. Dana, 9 inch... any major manufacturer can provide the needed components. First the question is what is rear wheel not engine dyno and then how much rubber can you run. 335 with tubed wells, axle is not the issue. Figure out how far you are going for tire fitment, how big of wells and what is the weight and work back from that. The HP is a singular dimension.

It should very conservatively make 1000 at the motor on pump gas. More if I get aggressive with it. AMC 426 stroker with an 83mm. Because it's a turbo car I will be launching off the transbrake on boost with a 28" slick at the strip.

I've been reading up on the Wavetrac, it sounds like the way to go. Any objections to the 33 spline for an 8.8? I've got an 8.8 in my other car and it would be nice to consolidate spare parts.

[intocarss]

What size axles should you be running to be sure that you will not break one?


A simple formula can be used to help you find the absolute maximum torque your car can put to the ground. To find the maximum torque, take the (Torque of your car) x (Your first gear) x (Your rear end gear ratio) x (90% efficiency).


For example, let's say your racecar has 600ft.lbs. of torque, you have a powerglide transmission with a 1.86 first gear ratio, and you have a 4.88 gear in your rear end. When you put those numbers into the formula, you get the following:




600ft.lbs. (torque)
x 1.86 (first gear)
x4.88 (rear gear)
x.90 (efficiency)
4901 ft.lbs. of Torque


This is the maximum torque transmitted to both rear axles if the tires have perfect adhesion to the track, a and you launch the car at its torque peak.


The torque rating of Moser Custo Alloy Axles are as stated.

30 Splin- 6,200 ft.lbs. (per axle)
31 Splin- 7,000 ft.lbs. (per axle)
33 Splin- 8,200 ft.lbs. (per axle)
35 Splin- 9,600 ft.lbs. (per axle)
40 Splin- 12,000 ft.lbs. (per axle)

[chetly]

There is nothing wrong with using a locker in a car that goes aroubd corners. Many championship winning SCCA AUTO-X use lockers. Mike Maier (5 time CP champ) and Brian Hobaugh (2nd this year at SCCA national championships and 2nd overall at OUSCI) both have lockers in their cars and they seem to do alright.

As far as axle size, no idea but id say at least a fabricated floater housing with bracing, nodular case, 35+ splines...